The purpose of this 9 nursing homes (NH) cluster randomized study is to determine whether repositioning frequency can be extended for NH residents who are low, moderate, and high risk for pressure ulcer (PrU) development and on visco-elastic (VE) high-density foam support-surfaces without compromising PrU incidence. We also will determine how changes in medical severity interact with changes in risk level and repositioning schedule to predict PrU development. PrUs result primarily from pressure over bony prominences that occlude blood flow to tissues. Current PrU prevention protocols recommend repositioning moderate, high, and severe risk residents a minimum of every 2 hours. We propose to include low risk residents because studies suggest they too develop PrUs. New pressure redistribution mattresses may make 2 hour repositioning unnecessary, but optimal time between repositioning remains unclear. Aims are 1) determine differences in incidence of new PrUs in NH residents (low, moderate, high risk level) using VE surfaces and repositioned at 2, 3, and 4 hour frequencies; and 2) determine how medical severity components (measured by a modified Comprehensive Severity Index), changes in clinically assessed risk-level (low, moderate, high as measured by Braden Scale), repositioning schedule, and their interactions are associated with PrU development; and an Exploratory Aim: Evaluate PrU prevention intervention approach between NH groups repositioned at 2, 3, or 4 hour by: 1) comparing the intervention resource costs (VE surfaces, Leaf service/sensor use, fixed and variable labor costs for training and repositioning) and incremental cost-effectiveness ratio of cost per % reduction in PrUs, and 2) exploring staff and resident satisfaction with intervention approach. We will randomly assign each NH to one of 3 study arms (2, 3, 4 hour) while providing standard nursing care. Leaf(r) triaxial accelerometers will be worn continuously to monitor repositioning. Periodic safety and care checks will be performed to ensure skin integrity. Residents admitted to study NHs for at least 3 days during the 6 week intervention, without an existing PrU, not using a specialty support surface, and of low, moderate, or high risk for PrU development will be included in analysis based on intention to treat. The outcome, no difference in PrU incidence, will determine whether repositioning frequency can be extended for low, moderate, high risk residents. Medical severity components and clinically assessed risk level will be examined for assessment to assessment change in relation to PrU development, thus identifying severity components associated with new PrUs. Data will be monitored by investigators daily. Data analysis and management will be performed by HSIR. NH staff and resident satisfaction with the intervention approach will be explored using focus groups. This study will advance knowledge about repositioning frequency and clinically assessed PrU risk-level in relation to medical severity. Outcomes of this research will contribute to future guidelins for more precise preventive nursing practices and refinement of PrU prevention guidelines.